1 86 BRAINS OF RATS AND MEN 



the top of a food-box (Fig. 46) and here depress a lever 

 {B of the figure) which opens the door of the food-box. 

 After destruction of the frontal part of the cortex, in- 

 cluding the electrically excitable field, the rats learned 



Fig. 46. — The inclined plane box. Jy door of restraining cage; 5, 

 inclined plane; C, catch extending down to upper edge of door; 7), door 

 leading into food-box. After Lashley. 



this habit as readily as do normal rats and they 

 showed no obvious sensori-motor defects. 



If previously trained and then operated upon, the 

 temporal regions of the cortex can be removed with- 

 out loss of the habit, but if the whole of the frontal 

 regions is destroyed this habit is lost. Partial destruc- 

 tion of the frontal regions does not totally abolish the 

 habit, but no particular part is necessary. *'In the 



